The SU-76 was off to a rocky start in early 1943, and was eventually replaced in production by the more reliable SU-76M. Meanwhile, there was another SPG that could have possibly replaced it, had the stars aligned:
"Both [SU-74-B and SU-74-D] vehicles were deemed acceptable for use by the Red Army as a result of government trials at the NIABG proving grounds, but were not accepted into production, as a lot of time and effort would have been needed to modernize and supercharge the ZIS-16 engine and there was an insignificant number of imported GMC-4-71 engines in the USSR.
The creation of both the SU-74-B and SU-74-D made it possible to develop a new type of SPG, the GAZ-75, in a record time of 26 days. The vehicle passed factory trials and was presented for trials at the NIABG proving grounds in December of 1943. The vehicle is equipped with a GAZ-203 supercharged engine with an output of 170 hp at 3600 RPM. It is armed with an 85 mm gun."